The invention relates to a lifting apparatus, in particular cable winch.
There is already known, from German patent application DE 43 10 770 A1, a motor-operated cable winch for lifting work in theatres. This motor-operated cable winch is driven by an electric drive motor which acts on a cable drum via a transmission. The transmission is disposed, together with two brakes, within the cable drum. The cable drum is mounted at both ends in a base frame which substantially consists of two mutually spaced-apart base plates orientated in parallel with each other. The base plates each have a substantially rectangular shape and are attached together via four longitudinal beams orientated in parallel with the longitudinal axis of the cable drum. The longitudinal beams are formed as spacer pipes which are each connected to the base plates in their corner regions by means of a tie rod guided within the spacer pipe and threaded nuts screwed thereto at the ends. The planar end surfaces of the spacer pipes lie against the inner sides of the base plates in the region of through-bores for the tie rods.
Moreover, the introduction to the description of German patent application DE 196 02 927 A1 discloses lifting apparatuses, in particular electric cable winches, which are constructed in a modular fashion from the electronics, motor, transmission, cable drum, support means and base frame assemblies. The individual assemblies can be fitted together in a plurality of combinations. The main assemblies of the lifting apparatus are attached to the base frame, in particular the cable drum is mounted at that location. The base frame consists at least of two base plates which are disposed in parallel with each other at a spaced disposition and are connected together via longitudinal beams. At least three screw connections are provided on each end plate for attaching the longitudinal beams thereto.
The German patent application DE 196 02 927 A1 itself relates to a base frame for cable winches which is to be characterised by a reduced assembly outlay and a reduced weight. The base frame consists substantially of the two base plates which are connected together via an upper and a lower u-shaped longitudinal beam and a traction element coinciding with the rotational axis of the cable drum in parallel with the beams. The traction element consists of solid material, threaded portions being disposed on the opposite ends of which, forming a shoulder. On one side, the traction element is screwed with its threaded portion into an internal thread disposed centrally in a base plate and with its annular shoulder lies against the planar inner side of the base plate via a disk. A through-bore is provided centrally in the opposite base plate and is formed in a stepped manner for forming an annular bearing surface for receiving the shoulder of the pipe at the beginning of the threaded rod portion. The threaded rod portion is guided through the through-bore and is braced from the outside with the outer side of the base plate via a threaded nut. The two u-shaped longitudinal beams are inserted into suitable blind hole-like recesses in the inner sides of the base plates and are held at that location between the base plates by the clamping force built up by the traction means.
In these embodiments in accordance with the Prior Art, the connecting elements between the base plates are formed as profiled sections with a solid circular cross-section or tubular cross-section, the ends of which protrude into, or lie against, corresponding bores or correspondingly worked bearing surfaces in the mutually facing surfaces of the base plates. Attachment is then effected via a screw connection which braces the profiled sections in their longitudinal direction with the base plates. These connection points between the profiled sections and the base plates can transfer axial forces in the direction of the longitudinal axis of the connecting elements or the cable drum and also so-called corner moments. “Corner moments” is understood here to mean moments which arise e.g., owing to twisting of the base frame at the connection points between the base plates and connecting elements. At the same time, the precise distance and the parallelism between the two base plates within the desired tolerances are provided by the length of the profiled sections.
Furthermore, German patent DE 10 2005 029 113 B3 discloses a base frame of a lifting apparatus which also comprises two base plates disposed in parallel with each other and at a spaced disposition with respect to each other. The base plates are releasably connected together and spaced apart from each other via longitudinal beams. For this, the ends of the longitudinal beams penetrate into blind hole bores in the mutually facing inner sides of the base plates and are pressed therein against a bearing surface in the blind hole bores and thus transversely with respect to the longitudinal direction of the longitudinal beam via screws.
U.S. Pat. No. 5,947,450 A describes a manual cable winch having a base frame which consists of two base plates and tubular longitudinal beams. The base plates are spaced apart from each other via the longitudinal beams and are connected together via their mutually opposing ends, the end surfaces of which lie against, and are supported on, the inner sides of the base plates. For this purpose, each longitudinal beam is provided with a threaded bar which is inserted through the corresponding longitudinal beam and through-openings provided in the base plates. Threaded nuts are screwed onto the mutually opposing ends, protruding from the outer sides of the base plates, of the threaded bars, whereby the base plates disposed between the end surfaces of the longitudinal beams and the threaded nuts are braced with the longitudinal beams.
JP 48 056761 U discloses a comparable base frame of a lifting apparatus having sleeve-shaped longitudinal beams and threaded bars. Two longitudinal beams are allocated to each threaded bar and are supported on the inner side of the associated base plate and also on suspension plates disposed between the base plates.
FR 2 928 637 A1 discloses a base frame of a lifting apparatus whose two base plates and the tubular longitudinal beams supported on the inner sides of the base plates and spacing them apart from each other are braced together via screws.
US 2009/308826 A1 discloses a base frame of a lifting apparatus whose tubular longitudinal beams are braced with two base plates by means of tubular clip-like holding elements. The longitudinal beams are inserted through holding elements attached in corner regions of the base plates and are fixedly clamped via screws acting transversely with respect to the longitudinal axis of the longitudinal beam.
The constructional elements of the lifting apparatus referred to previously as base plates can also be housing parts which fulfil different functions of the lifting apparatus. For example, these are used for attaching the lifting drive, for supporting the cable drum, for mounting cross-beams for parts of the cable reeving arrangement, for receiving the electric equipment, for attaching the feet of the lifting apparatus or for mounting parts of travelling mechanisms.
From this it results that the threaded nuts or screws for attaching the longitudinal beams to the base plates are often disposed in a poorly accessible location, e.g., in the housing interior. These connection locations also frequently have to be moved out of the housing in order to be accessible. This complicates assembly and the housing in the form of the base plates has to be enlarged needlessly.